The combined effect of surgeon and hospital volume on health outcomes: a systematic review.

To explore the interaction between surgeon volumes (SVs) and hospital volumes (HVs) on health outcomes. We searched MEDLINE, Embase, CINAHL, Web of Science as of May 2017. We included studies investigating the interaction between high or low SVs operating in high or low HVs. Review process follows the PRISMA guidelines. We assessed the methodological quality of the included studies using validated critical appraisal checklists. Sixteen studies were included. Due to the heterogeneity of studies, it was not possible to perform a quantitative analysis. Heath outcome are worse when high SV operating in low HV vs high HV, for the majority of the conditions (colorectal cancer, cystectomy, liver resection, mitral valve surgery, pancreatico-duodenectomy). Results for low SV are better when operating in high HV vs low HV for patients undergoing pancreatic-duodenectomy for mortality, 30 days complications and length of stay. Results for low SV are worse vs high SV when operating in high HV for most considered conditions. Results were in favour of higher SV vs low SV when operating in low HV for digital replantation success after injuries, 30 days mortality and complications after pancreatic-duodenectomy. The available evidence is limited. It is necessary to increase the monitoring of the association between surgeons volumes and hospitals volumes in which they operate, to ensure fairness and accuracy of care for better health outcomes.